Airbag module

ABSTRACT

The invention relates to an airbag system including an airbag including a vent and a vent cover, an actuator, and a tether. The tension can be applied to the tether when the actuator has not been activated. Further, when the actuator has not been activated, the vent is closed by the vent cover due to the tension applied to the tether connected to the vent cover. The actuator is configured, once inflation gas is supplied to inflate the airbag, to reduce or release the tension applied to the tether when the actuator is activated. The vent cover is configured to remain in position when the actuator has been activated until the inflation gas forces the vent open. The vent cover is configured to maintain the vent in a closed state when the actuator has not been activated. In addition, the vent cover can be located on an exterior surface of the airbag.

This application claims priority to and the benefit of U.S. ProvisionalPatent Application No. 61/325,628, filed Apr. 19, 2010, incorporated byreference herein in its entirety.

BACKGROUND

One issue addressed by airbag systems is the amount of internal pressurewithin an airbag during inflation of the airbag. For example, if anairbag has a relatively high internal pressure, it is possible for anoccupant to suffer an injury when the occupant contacts the airbag, suchas a head injury. Airbag systems and designs have addressed this issueby venting airbags when airbags inflate and providing airbags with fixedvents, passive vents, and active vents. Further improvements can be madein airbag system design to further reduce occupant injuries. Inaddition, further improvements can be made to accommodate occupants ofvarious sizes and to accommodate occupants out of position in a vehicle.

SUMMARY

The present application relates generally to the field of airbags foruse in motor vehicles. More specifically, this application relates to anairbag module with an electromechanical active cushion venting mechanismto control internal chamber pressure of the airbag cushion to reduceacceleration and forces of the occupant, such as the head and neck ofthe occupant, during airbag deployment to improve occupant safety.

According to an example, an airbag system for a vehicle comprises anairbag including a vent and a vent cover configured to close the vent,an actuator, and a tether. The tether can be connected between theactuator and the vent cover such that tension is applied to the tetherwhen the actuator has not been activated. Further, when the actuator hasnot been activated, the vent is closed by the vent cover due to thetension applied to the tether connected to the vent cover. The actuatoris configured, once inflation gas is supplied to inflate the airbag, toreduce or release the tension applied to the tether when the actuator isactivated. The vent cover is configured to remain in position when theactuator has been activated until the inflation gas forces the ventopen. The vent cover is configured to maintain the vent in a closedstate when the actuator has not been activated. In addition, the ventcover can be located on an exterior surface of the airbag.

The tether can be connected between the actuator and the vent cover suchthat tension is applied to the tether when the actuator has not beenactivated. When the actuator has not been activated, the vent can beclosed by the vent cover due to the tension applied to the tetherconnected to the vent cover. Once inflation gas is supplied to inflatethe airbag, the actuator is configured to reduce or release the tensionapplied to the tether when the actuator is activated. The vent cover isconfigured to remain in position when the actuator has been activateduntil the inflation gas forces the vent open. The vent cover isconfigured to maintain the vent in a closed state when the actuator hasnot been activated.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an exemplary motor vehicle having anairbag module.

FIG. 2 is a side view of a passenger compartment of a motor vehicleillustrating an example of an airbag system or module having anelectromechanical active cushion venting mechanism, with the airbagcushion shown deployed or unfolded.

FIG. 3 is a side view of the airbag system or module of FIG. 2 showndeployed or unfolded.

FIG. 3A is a sectional view of the airbag module of FIG. 3, taken alongline A-A.

FIG. 3B is a front view of the airbag module of FIG. 3 shown deployed orunfolded.

FIG. 4 is a perspective view of an example of an airbag system ormodule, shown deployed or unfolded, having an electromechanical activecushion venting mechanism illustrated in the closed position.

FIG. 4A is a sectional view of the airbag system or module of FIG. 4.

FIG. 5 is a perspective view of an example of an airbag system ormodule, shown deployed or unfolded, having an electromechanical activecushion venting mechanism illustrated in the open position.

FIG. 5A is a sectional view of the airbag module of FIG. 5.

FIG. 6 illustrates a performance comparison between a conventionalairbag having a fixed vent and an exemplary airbag system or module, asdisclosed in this application, having an electromechanical activecushion venting mechanism.

FIG. 7 is an exploded view of another example of an airbag system.

FIG. 8A is a side view of an airbag system with an electromechanicalactive cushion venting mechanism in a closed position.

FIG. 8B is a sectional view of the airbag system of FIG. 8A along lineA-A.

FIG. 9A is a side view of an airbag system with an electromechanicalactive cushion venting mechanism in an open position.

FIG. 9B is a sectional view of the airbag system of FIG. 9A along lineB-B.

DETAILED DESCRIPTION

Airbag systems or modules are well known for providing improved occupantprotection during a dynamic vehicle event, such as a frontal or sideimpact. Airbag modules provide improved occupant protection or safety,during a dynamic vehicle event, by including an inflatable airbagcushion or airbag that deploys and inflates from gas rapidly pushed intothe airbag cushion by means of an inflator, whereby the cushion deploysbetween the occupant being protected and another portion of the vehicle,such as the dashboard or door assembly.

The airbag cushion may reduce displacement and acceleration of theoccupant reducing the forces and absorbing energy upon impact by theoccupant. An inflator or module may use a device, such as a pyrotechnicdevice or other airbag inflation device, to generate gas almostinstantaneously and to push the gas at a high volumetric flow rate intothe inflatable airbag cushion of the airbag system. Airbags may be usedto provide protection to any occupant located in any seating row (e.g.,first, second, third) of a vehicle.

Airbag modules and airbag cushions may be stored within and deployedfrom any vehicle component, such as the dashboard of steering column.Airbags are typically packaged through a process of folding and rollingto compact the airbag in order for it to fit into the smallcross-section of the storage area.

The airbag systems and modules disclosed herein can includeelectromechanical active cushion venting mechanisms to control theinternal pressure of the airbag cushion relative to time, during airbagdeployment, to improve occupant protection. For example, vehicle sensorsmay monitor crash severity and may communicate such measured inputparameters to a vehicle device, such as a control module, which maydetermine crash severity, then communicate with the airbag module totailor the airbag internal pressure through the electromechanical activecushion venting mechanism. The active venting mechanism may control theamount of gas permitted to escape through the active vent hole byadjustment of the vent hole cover, to tailor the internal airbagpressure to provide optimal occupant protection based on the crashseverity of the vehicle. The active venting mechanism may prohibit orsubstantially limit inflation gas from escaping the airbag cushion,during the initial moments of vehicle impact, in order for the internalpressure to build rapidly to increase the speed of deployment andinitial restraint of the occupant. The active venting mechanism maysubsequently control displacement of the vent hole cover to permit apredetermined amount of inflation gas to escape to reduce the internalpressure of the airbag cushion, which improves the ride down of theoccupant load and reduces the head acceleration, relative to a cushionhaving a higher stiffness or internal pressure.

FIG. 1 shows an example of a motor vehicle 10 which includes a passengercompartment having at least one airbag system or module 12, configuredto provide occupant protection. The vehicle illustrated may be a typicalsedan, but the airbag modules disclosed herein may be included in anymotor vehicle having at least one occupant. Additionally, the airbagmodules disclosed herein may be used to provide occupant protectionduring any vehicle impact event (e.g., frontal impact, side impact) andmay protect any occupant (e.g., driver, passenger), as the illustrationsherein are not meant as limitations.

FIG. 2 shows a side view of an example of a passenger compartment of amotor vehicle which includes an airbag system or module 20. The airbagmodule 20 is shown in a deployed state from the instrument panel 22 ofthe vehicle, providing a degree of front impact protection to the seatedoccupant 24.

According to an example, the airbag system or module may include anairbag cushion or airbag 26, an inflator for inflating the airbagcushion, and an electromechanical active cushion venting mechanism. Asshown in the example of FIG. 2, the airbag 26 can extend along theinterior of the windshield 23 of a vehicle when the airbag 26 deploysand inflates. The airbag cushion 26 may comprise one or a plurality ofpanels made from conventional airbag material, such as a high-strengthwoven fabric, coupled together by stitching (or other suitable methods)to form at least one inflatable portion or chamber. The airbag cushionmay be coupled to an inflator 28, so that inflation gas generated by theinflator flows into and expands the inflatable portion of the airbagcushion 26, increasing the internal pressure of the cushion, whileunfolding and deploying the airbag cushion 26 to provide a degree ofprotection to an occupant. According to another example, activation ofthe airbag system or module by another vehicle device, such as a controlmodule, may initiate the inflator 28 to inflate the airbag cushion 26.The airbag cushion 26 may include one or a plurality of apertures orvent holes to permit inflation gas to escape during airbag deployment.The vent holes may be configured to form any suitable shape, such asround, and any suitable size. Thus, vent hole configuration may betailored to specific performance characteristics. For example, theairbag 26 can include, as shown in the example of FIG. 2, a primary vent30 and an active venting vent 32.

According to an example, the airbag system or module 20 includes anelectromechanical active cushion venting mechanism includes a vent holecover or vent cover 40, a strap (or tether) 34, and a release mechanismor actuator 36. As shown in the drawings, the vent cover can be externalto the airbag. In addition, the tether 34 can be located, for example,within an interior of the airbag and can remain within an interior ofthe airbag during inflation of the airbag and use of theelectromechanical active cushion venting mechanism. For example, thetether 34 can be located within an interior the airbag before inflationof the airbag and can remain within the interior of the airbag duringinflation of the airbag and use of the electromechanical active cushionventing mechanism, except for the portion of the tether 34 connected toan external cover 40. The actuator 36 can be, for example, a pyrotechnicactuator or other actuator used in the art. FIG. 3 shows a side view ofthe airbag system 20 of FIG. 2 with an example of the vent cover 40 indetail. FIG. 3B shows a front view of the of the airbag system 20 ofFIG. 2, with the venting mechanism located on a side panel 42 of theairbag 26. The vent hole cover 40 may be made of high-strength wovenfabric or other suitable material and is configured to cover the venthole to prohibit inflation gas from escaping through the vent hole ofthe airbag cushion. The size and shape of the vent hole cover 40 may betailored based on the size and shape of the vent hole 32.

As shown in the example of FIG. 3A, the vent hole cover 40 may becoupled, such as, for example, by stitching 44, at one end to the tether34 and coupled, such as by stitching 46, at another end to the airbagcushion 26 to maintain a position of the vent hole cover 40 to cover thevent hole 32 of the cushion. Such a connection to couple the vent cover40 to the airbag 26 can result in a tension being applied to the tether34 due to the tether 34 being connected between the vent cover 40 andthe actuator 36 when the actuator 36 has not been activated. Thus, thetether 34 can be connected between the actuator 36 and the vent cover 40such that tension is applied to the tether 34 when the actuator 36 hasnot been activated. In turn, the tension applied to the tether 34 canalso be applied to the vent cover 40. Thus, when the actuator 36 has notbeen activated, the vent 32 can be closed by the vent cover 40 due tothe tension applied to the tether 34 connected to the vent cover 40. Asshown in the example of FIG. 3A, the vent cover 40 can be located on anexterior surface of the airbag 26. The vent cover 40 is configured tomaintain the vent 32 in a closed state when the actuator 36 has not beenactivated. The tension applied to the tether 34, and in turn the ventcover 40, is sufficient to maintain the vent 32 in a closed state whenthe actuator 36 has not been activated, despite the inflation gassupplied to inflate the airbag 26 on the gas side X of the airbag 26.

For example, the vent hole cover or vent cover 40 may be coupled to theairbag cushion, such as by stitching 46, at the end of the vent cover 40opposite to the end which is coupled to the tether 34, so that thecoupling, such as the stitching 46, between the vent hole cover 40 andthe cushion acts like a hinge. As a result, when tension on the strap ortether 34 is reduced, the pressure exerted from the inflation gas ontothe vent cover 40 can overcome the reduced tension in the strap ortether 34, causing the vent cover 40 to be moved or displaced away fromthe vent hole 32. Otherwise, the vent cover 40 is configured to remainin position when the actuator 36 has been activated until the inflationgas forces the vent 32 open, due to the coupling of the vent cover 40 tothe airbag 26.

For example, once the actuator 36 has been activated to reduce orrelease the tension applied to the tether 34, the pressure of theinflation gas within the airbag 26 can cause the vent cover 40 to moverelative to the vent 32. For example, the vent cover 40 can sliderelative to the vent 32 when the vent cover 40 is moved by the inflationgas. According to another example, the vent cover 40 can pivot relativeto the vent, such as about the coupling connecting the vent cover 40 tothe airbag 26.

An open position of the vent hole cover 40 permits inflation gas toescape through the vent hole, which reduces the internal pressure of theairbag cushion. Such reduced pressure can advantageously be used toreduce the firmness of the airbag to accommodate different sizes ofoccupants, occupants out of positions, or to generally reduce injuriesto an occupant. Conversely, tension in the strap may be maintained bythe active venting mechanism or actuator 36, so that the tensionovercomes the pressure exerted on the vent hole cover by the inflationgas, to maintain the vent hole cover 40 over top of and covering thevent hole 32, thus prohibiting inflation gas from escaping through thevent hole 32. Therefore, this closed position of the vent hole cover 40can cause inflation gas to remain trapped inside the airbag chamber,thus increasing the internal pressure (and stiffness) of the airbagcushion.

FIG. 4 shows an example of an airbag system in which the deployment andinflation of the airbag of the airbag system has been initiated and thevent cover 40 remains in a closed position to close the vent 32. In sucha state the actuator 36 has not been actuated to reduce or release thetension applied to the tether 34, causing the tether 34 to remain undertension and the vent cover 40 to remain in a closed position to coverthe vent 32. FIG. 4A shows a sectional view of the airbag system of FIG.4, which shows the vent cover 40 in the closed position to cover thevent 32 and prevent or substantially prevent inflation gas on the gasside X of the airbag from venting through the vent 32.

FIG. 5 shows an example of an airbag system in which the deployment andinflation of the airbag of the airbag system has been initiated but thevent cover 40 has been moved to an open position to allow inflation gasto vent through the vent 32. For example, the actuator 36 has beenactivated to reduce or release the tension applied to the tether 34,which in turn reduces or release the tension or force applied to thevent cover 40. In such a state, as shown in the examples of FIG. 5 andFIG. 5A, the force and pressure exerted by the inflation gas within theairbag can be sufficient to move the vent cover 40 so that vent cover 40is moved to an open position which permits inflation gas to vent throughthe vent 32. For example, the inflation gas can cause the vent cover 40to slide relative to the airbag, such as to a side of the vent 32, tolift above the vent, such as to provide a clearance between the openingof the vent 32 and the vent cover 40, to swing open like a door on ahinge, or by other movements.

The tension of the strap or tether 34 may be controlled by theelectromechanical active cushion venting mechanism. As shown in theexamples of the drawings, the tether may include a first end coupled tothe vent hole cover and a second end coupled to a release mechanism oractuator. For example, a length of the strap or tether may be tailoredbased on the distance, when the airbag is deployed, from the actuator tothe vent hole cover. The tether may be positioned inside the airbagcushion, on the outside of the airbag cushion, or may pass from theone-side of the cushion to the other-side of the cushion through a slitor aperture in the cushion panel.

The release mechanism or actuator may communicate with another vehicledevice, such as the control module, whereby the control module mayactuate the actuator, such as during a vehicle dynamic event whichtriggers airbag deployment, based on input from vehicle sensors. Whenthe actuator is actuated, the actuator reduces or releases the tensionapplied to the tether, which allows the end of the tether coupled to theactuator to move freely. Thus, the vent cover is permitted to move tothe open position, such as when the pressure of the inflation gas withinthe airbag causes the vent cover to move aside, whereby the inflationgas may escape through the vent hole. When the actuator has notactuated, the end of the tether or strap coupled to the actuator may beprohibited from moving freely, such that the tether may be subjected totension. Thus, the vent cover can remain in a position to cover the venthole to prohibit the escape of inflation gas through the vent hole.

According to another example, an electromechanical active cushionventing mechanism includes a vent hole cover, a strap (or tether), and adisplacement mechanism or actuator. The vent hole cover may beconfigured as discussed herein. The strap may include a first end andsecond end. The first end of the strap may couple to the vent hole coveras discussed herein, and the second end of the strap may couple to thedisplacement mechanism. The displacement mechanism may communicate withanother vehicle device, such as the control module, whereby the controlmodule may actuate the displacement mechanism, during a vehicle dynamicevent triggering airbag deployment, based on input from vehicle sensors.

According to an example, the displacement mechanism or actuator mayunwind the strap, so that the length of the strap is increased or thestrap is extended, so that tension in the strap is reduced or releasedaccordingly. When the actuator is actuated, the strap can extend orunwind from the actuator, reducing or releasing the tension in thestrap, depending on the length of strap extended or unwound, permittingthe vent hole cover to move to the open position and allow inflation gasto escape through the vent hole. The length of strap extended or unwoundmay vary based on the input from the vehicle sensors, such that thelength may be tailored to crash severity. Thus, the length extended maybe tailored to control the amount of inflation gas that is permitted toescape through the vent hole.

According to another example, the actuator of the electromechanicalactive cushion venting mechanism may be configured to unwind and windthe tether or strap. Thus, during the initial stage of deployment of theairbag cushion, the strap may be in tension to keep the vent hole coverin the closed position and prohibit inflation gas from escaping, thusspeeding deployment of the cushion. Then during the intermediate stageof deployment of the airbag cushion, the strap or tether may be unwoundto release the tension in the strap or tether, allowing the vent coverto move to the open position and permit inflation gas to escape from theairbag cushion. For example, during a later stage of deployment of theairbag cushion, the strap or tether may be wound to place the strapunder tension and to move the vent hole cover to the closed position toprohibit inflation gas from escaping.

According to another example, an electromechanical active cushionventing mechanism includes a vent hole cover or vent cover, a strap ortether, and a displacement mechanism or actuator. The vent hole covermay be configured as discussed herein. The tether may include a firstend coupled to the vent hole cover, a second end coupled to the airbagand a mid-portion located between the first and second ends. Themid-portion may include a length limiting mechanism, such as a fold, aneyelet, a slit, a loop, a pinch, or a tear stitch. The length limitingmechanism may provide tension during airbag deployment. During an airbagdeploying event, a control module may communicate to the airbag systemor module, including the actuator or displacement mechanism, to reduceor remove the tension in the mid-portion by allowing the tether tolengthen, which allows the vent hole cover to move to an open positionto permit inflation gas to escape. During deployment, the second end ofthe strap may remain coupled to the airbag module and/or the first endof the strap may remain coupled to the vent hole cover, which may remaincoupled to the airbag cushion. This reduces the possibility of the endsof the strap contacting the occupant during deployment of the airbagcushion.

FIG. 6 includes a graph illustrating pressure over time to compare aconventional airbag having a fixed passive venting system to anexemplary airbag having an electromechanical active cushion ventingmechanism, as discussed herein. Additionally, FIG. 6 includes a graphillustrating the head acceleration of an occupant over time to compare aconventional airbag having a fixed passive venting system to anexemplary airbag having an electromechanical active cushion ventingmechanism, as discussed herein. The solid lines in FIG. 6 show theperformance of the conventional airbag while the dashed lines in FIG. 6show the performance of the exemplary airbag. As shown in the example ofFIG. 6, the exemplary airbag according to the invention can provide areduction or pressure when an airbag is inflated and a reduced amount ofhead acceleration, which can reduce the injuries to an occupant, such ashead injuries.

FIG. 7 shows an exploded view of another example of an airbag system 50with an electromechanical active cushion venting mechanism. As shown inthe example of FIG. 7, the airbag of the airbag system 50 can include amain panel 52, one side panel 54, and another side panel 56. One or bothof the side panels can include a vent opening or hole 58 and one of theside panels can include an active vent opening or hole 60. According toanother example, the vent opening or hole 60 is located in the mainpanel 52. According to another example, the vent opening or hole 60 islocated in any panel of an airbag or in an airbag formed by a singlepanel. In addition, an airbag can have more than one electromechanicalactive cushion venting mechanism, such as one on each side of the airbagand in locations according to the design and use of the airbag.

As shown in the example of FIG. 7, a cover base 62 can be connected to aside panel 56 at the active vent opening 60, such as by stitching orother means used in the art. The airbag system 50 can further include atether 72 connected to a vent cover 70 which is placed over the coverbase 62 and the active vent 60. The tether 72 can be directed from aninterior of the airbag to an exterior, such as through an opening 74 inthe airbag, as shown in the example of FIG. 7. As discussed herein, thevent cover 70 can be located on an exterior surface of the airbag. Apocket 64 can also be provided to cover the opening and at least aportion of the cover 70, such as where the tether 72 is connected to thecover 70. The airbag system 50 can further include an actuator 80configured to reduce or release tension applied to the tether 72, asshown in the examples of FIG. 8B and FIG. 9B.

The cover base 62 can be, for example, a piece of fabric attached to theside panel 56 around the active vent hole 60. In addition, the coverbase 62 can be attached to the cover 70, such as by stitching around theperimeter of the cover base 62 and cover 70, except on one side whichremains open for venting. The cover base 62 can improve sealing on thesides of the cover 70. Another advantage of such a configuration is thatthe improved sealing allows the cover 70 to build up pressure which willhelp to open the cover 70 at an earlier time after the tension appliedto the tether 72 has been reduced or released. The cover base 62includes a hole 63, as shown in the example of FIG. 7. The hole 63 canbe the same size and shape as the vent opening or hole 60 or the sizeand/or shape of the hole 63 of the cover base 62 can be a different sizeand/or shape as the vent opening or hole 60, such as to control the flowof inflation gas through the vent opening or hole 60 and the hole 63 andinto a space formed between the cover base 62 and the cover 70.

The pocket 64 can be, for example, a piece of fabric attached toexterior of the side panel 56. The pocket 64 can help to keep the ventcover 70 in place during folding of the airbag. The pocket 64 can alsoimprove sealing of active vent cover 70 before the active vent 60 isopened.

FIG. 8A shows a side view of an exemplary airbag system in which thecover 70 is in a closed position over the active vent opening 60, suchas before an actuator 80 has been activated and tension remains appliedto a tether 72. FIG. 8B is a section view of the airbag system of FIG.8A along line A-A. As shown in the examples of FIG. 8A and FIG. 8B, thepocket 64 can be located over at least a portion of the cover 70, suchas where the tether 72 is connected to the cover 70. According to anexample, the cover base 62 and the cover 70 can cooperate to provide aclamshell design due to the cover base 62 and the cover 70 beingconnected to one another and placed on top of one another. As shown inthe example of FIG. 8B, a second or additional chamber 71 can beprovided between the cover 70 and the cover base 62. The second oradditional chamber 71 can become pre-pressurized by inflation gas, whichcan make movement and opening of the cover 70 to open the vent opening60 easier. For example, the second or additional chamber 71 can bepre-pressurized before an actuator has been activated to reduce orrelease tension applied to a tether or the second or additional chamber71 can become pre-pressurized after an actuator has been activated butbefore inflation gas within the airbag has moved the cover 70 to openthe vent. Further, the pocket 64 can aid in the sealing of the cover 70and the cover base 62 over the active vent 60, such as by pressingdownwards on the cover 70 and the cover base 62 against the panel of theairbag. In addition, the pocket 64 can aid in permitting the second oradditional chamber 71 to be pre-pressurized before the cover 70 is movedto permit inflation gas to escape from the vent opening 60, such as byholding or clamping down an edge of the cover 70 and the cover base 62either before an actuator has been activated or after the actuator hasbeen activated but before the inflation gas has moved the cover 70 topermit inflation gas to escape.

FIG. 9A shows a side view of an exemplary airbag system in which thecover 70 is in an open position over the active vent opening 60, such asafter an actuator 80 has been activated and tension applied to a tether72 has been reduced or released. FIG. 9B is a section view of the airbagsystem of FIG. 9A along line B-B. As shown in the example of FIG. 9B,once the tension applied to the tether 72 has been reduced or releasedthe pressure of the inflation gas on the gas side X of the airbag can besufficient to move or displace the cover 70 to result in the opening ofthe active vent 60. For example, the inflation gas can cause thesecondary or additional chamber 71 to become further pressurized andinflated, causing the cover 70 to move relative to the active vent 60.Further, because the cover base 62 can be connected to the cover 70,when the cover 70 is moved by the force or pressure of the inflationgas, the cover base 62 can also move. For example, the cover 70 and thecover base 62 can be lifted upwards relative to the active vent 60 andthe panel of the airbag, as shown in the example of FIG. 9B. The cover70 and the cover base 62 can cooperate or be joined together, such as ina clamshell configuration, to provide an opening 73 for the inflationgas escaping from the active vent 60 to pass through and exit theairbag. The opening 73 can have the same shape and/or size as the activevent 60 and/or the opening 71 in the cover base 62 or can have adifferent shape and/or size than both or either of these openings, suchas to control or affect the flow of inflation gas.

As utilized herein, the terms “approximately,” “about,” “substantially”,and similar terms are intended to have a broad meaning in harmony withthe common and accepted usage by those of ordinary skill in the art towhich the subject matter of this disclosure pertains. It should beunderstood by those of skill in the art who review this disclosure thatthese terms are intended to allow a description of certain featuresdescribed and claimed without restricting the scope of these features tothe precise numerical ranges provided. Accordingly, these terms shouldbe interpreted as indicating that insubstantial or inconsequentialmodifications or alterations of the subject matter described and claimedare considered to be within the scope of the invention as recited in theappended claims.

It should be noted that the term “exemplary” as used herein to describevarious embodiments is intended to indicate that such embodiments arepossible examples, representations, and/or illustrations of possibleembodiments (and such term is not intended to connote that suchembodiments are necessarily extraordinary or superlative examples).

The terms “coupled,” “connected,” and the like as used herein mean thejoining of two members directly or indirectly to one another. Suchjoining may be stationary (e.g., permanent) or moveable (e.g., removableor releasable). Such joining may be achieved with the two members or thetwo members and any additional intermediate members being integrallyformed as a single unitary body with one another or with the two membersor the two members and any additional intermediate members beingattached to one another.

References herein to the positions of elements (e.g., “top,” “bottom,”“above,” “below,” etc.) are merely used to describe the orientation ofvarious elements in the FIGURES. It should be noted that the orientationof various elements may differ according to other exemplary embodiments,and that such variations are intended to be encompassed by the presentdisclosure.

It is important to note that the construction and arrangement of theairbag modules as shown in the various exemplary embodiments isillustrative only. Although only a few embodiments have been describedin detail in this disclosure, those skilled in the art who review thisdisclosure will readily appreciate that many modifications are possible(e.g., variations in sizes, dimensions, structures, shapes andproportions of the various elements, values of parameters, mountingarrangements, use of materials, colors, orientations, etc.) withoutmaterially departing from the novel teachings and advantages of thesubject matter described herein. For example, elements shown asintegrally formed may be constructed of multiple parts or elements, theposition of elements may be reversed or otherwise varied, and the natureor number of discrete elements or positions may be altered or varied.The order or sequence of any process or method steps may be varied orre-sequenced according to alternative embodiments. Other substitutions,modifications, changes and omissions may also be made in the design,operating conditions and arrangement of the various exemplaryembodiments without departing from the scope of the present invention.

What is claimed is:
 1. An airbag system for a vehicle, comprising: anairbag including a vent and a vent cover configured to close the vent, apocket panel, an actuator, and a tether, wherein the tether is connectedbetween the actuator and the vent cover such that tension is applied tothe tether and the vent cover when the actuator has not been activated,wherein, when the actuator has not been activated, the vent is closed bythe vent cover due to the tension applied to the vent cover by thetether, and the pocket panel overlaps and is positioned outward of atleast a portion of the vent cover, wherein, once inflation gas issupplied to inflate the airbag, the actuator is configured to reduce orrelease the tension applied to the tether when the actuator isactivated, wherein the vent cover is configured to remain in positionwhen the actuator has been activated until the inflation gas forces thevent open, wherein the vent cover is configured to maintain the vent ina closed state when the actuator has not been activated, wherein thevent cover is located on an exterior surface of the airbag.
 2. Theairbag system of claim 1, wherein the tension applied to the tether issufficient to maintain the vent in a closed state when the actuator hasnot been activated, despite the inflation gas supplied to inflate theairbag.
 3. The airbag system of claim 1, wherein the inflation gasforces the vent open once the actuator has been activated by moving thevent cover.
 4. The airbag system of claim 1, wherein the tether includesa loop between the actuator and the vent cover as a length limitingmechanism for the tether.
 5. The airbag system of claim 1, furthercomprising a vent base having an opening, wherein the vent base islocated between the vent cover and the vent.
 6. The airbag system ofclaim 5, wherein the vent base and the vent cover form a secondarychamber between the vent base and the vent cover which can bepre-pressurized.
 7. The airbag system of claim 1, wherein the vent is anopening in the airbag and the vent cover closes the vent by cover theopening.
 8. The airbag system of claim 1, wherein one end of the tetheris connected to the actuator and an opposite end of the tether isconnected to the vent cover.
 9. The airbag system of claim 1, whereinthe tether is located within the airbag before and after inflation ofthe airbag.
 10. The airbag system of claim 1, wherein the actuator is apyrotechnic actuator.
 11. The airbag system of claim 1, wherein theactuator is configured to change a length of the tether when theactuator is activated to reduce or release the tension applied to thetether.
 12. The airbag system of claim 11, wherein the actuator isconfigured to increase the length of the tether when the actuator isactivated to reduce or release the tension applied to the tether. 13.The airbag system of claim 1, wherein when inflation gas is supplied toinflate the airbag and when the actuator has not been activated, thepocket panel presses against the vent cover to improve sealing of thevent cover over the vent.
 14. The airbag system of claim 1 wherein, whenthe actuator has not been activated, the pocket panel covers a portionof the vent cover that is coupled to the tether.
 15. An airbag systemfor a vehicle, comprising: an airbag including a vent and a vent coverconfigured to close the vent, a pocket panel, an actuator, and a tether,wherein the tether is connected between the actuator and the vent coversuch that tension is applied to the tether when the actuator has notbeen activated, wherein, when the actuator has not been activated, thevent is closed by the vent cover due to the tension applied to thetether connected to the vent cover, and the pocket panel overlaps and ispositioned outward of at least a portion of the vent cover, wherein,once inflation gas is supplied to inflate the airbag, the actuator isconfigured to reduce or release the tension applied to the tether whenthe actuator is activated, wherein the vent cover is configured toremain in position when the actuator has been activated until theinflation gas forces the vent open, wherein the vent cover is configuredto maintain the vent in a closed state when the actuator has not beenactivated, wherein the vent cover is located on an exterior surface ofthe airbag; wherein at least a portion of the tether extends between thepocket panel and the airbag; and wherein the pocket panel covers anopening through which the tether extends.
 16. An airbag system for avehicle, comprising: an airbag including a vent, a vent cover configuredto close the vent, and a vent base having an opening, the vent basebeing located between the vent cover and the vent, an actuator, and atether, wherein the tether is connected between the actuator and thevent cover such that tension is applied to the tether when the actuatorhas not been activated, wherein, when the actuator has not beenactivated, the vent is closed by the vent cover due to the tensionapplied to the tether connected to the vent cover, wherein, onceinflation gas is supplied to inflate the airbag, the actuator isconfigured to reduce or release the tension applied to the tether whenthe actuator is activated, wherein the vent cover is configured toremain in position when the actuator has been activated until theinflation gas forces the vent open, wherein the vent cover is configuredto maintain the vent in a closed state when the actuator has not beenactivated, wherein the vent cover is located on an exterior surface ofthe airbag, and wherein the vent base and the vent cover are attached toeach other around perimeters thereof to form a secondary chamber betweenthe vent base and the vent cover which can be pre-pressurized by theinflation gas prior to activating the actuator.
 17. The airbag system ofclaim 16, wherein at least a portion of the perimeters of the vent baseand the vent cover are not coupled to each other to allow venting fromthe secondary chamber.
 18. The airbag system of claim 17, wherein thevent base and the vent cover are not coupled to each other along a sideof the vent cover that is coupled to the tether.
 19. The airbag systemof claim 16, further comprising a pocket panel, wherein, after inflationgas is supplied to inflate the airbag and when the actuator has not beenactivated, the pocket panel overlaps and is positioned outward of atleast a portion of the vent cover.